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linux/kernel/sched
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Wanpeng Li 62208707b4 sched/cputime: Fix prev steal time accouting during CPU hotplug 
commit 3d89e5478b upstream.

Commit:

  e9532e69b8 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")

... set rq->prev_* to 0 after a CPU hotplug comes back, in order to
fix the case where (after CPU hotplug) steal time is smaller than
rq->prev_steal_time.

However, this should never happen. Steal time was only smaller because of the
KVM-specific bug fixed by the previous patch.  Worse, the previous patch
triggers a bug on CPU hot-unplug/plug operation: because
rq->prev_steal_time is cleared, all of the CPU's past steal time will be
accounted again on hot-plug.

Since the root cause has been fixed, we can just revert commit e9532e69b8.

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 'commit e9532e69b8 ("sched/cputime: Fix steal time accounting vs. CPU hotplug")'
Link: http://lkml.kernel.org/r/1465813966-3116-3-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andres Oportus <andresoportus@google.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-08-06 19:19:43 -07:00
..
auto_group.c
auto_group.h
clock.c treewide: Remove old email address 2015-11-23 09:44:58 +01:00
completion.c
core.c sched/cputime: Fix prev steal time accouting during CPU hotplug 2017-08-06 19:19:43 -07:00
cpuacct.c
cpuacct.h
cpudeadline.c sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpudeadline.h sched/deadline: Unify dl_time_before() usage 2015-09-23 09:51:25 +02:00
cpupri.c
cpupri.h
cputime.c sched/cputime: Fix NO_HZ_FULL getrusage() monotonicity regression 2016-09-07 08:32:41 +02:00
deadline.c sched/rt: Add a missing rescheduling point 2017-03-31 09:49:54 +02:00
debug.c
fair.c sched/fair: Initialize throttle_count for new task-groups lazily 2017-05-25 14:30:12 +02:00
features.h sched/fair: Convert arch_scale_cpu_capacity() from weak function to #define 2015-09-13 09:52:55 +02:00
idle_task.c
idle.c sched, tracing: Stop/start critical timings around the idle=poll idle loop 2015-10-12 09:45:25 +02:00
loadavg.c sched/loadavg: Avoid loadavg spikes caused by delayed NO_HZ accounting 2017-07-05 14:37:21 +02:00
Makefile
rt.c sched/rt: Add a missing rescheduling point 2017-03-31 09:49:54 +02:00
sched.h sched/cputime: Fix prev steal time accouting during CPU hotplug 2017-08-06 19:19:43 -07:00
stats.c
stats.h
stop_task.c
wait.c sched/wait: Fix the signal handling fix 2015-12-13 14:30:59 -08:00